Lesser metatarsophalangeal joint (MPJ) instability defines a clinical problem that presents as varied degrees of sagittal and/or transverse, and/or frontal plane instability of the “internal” toes (second, third and fourth). Pathology can vary from mild inflammation of periarticular soft tissues with minimal positional changes of the toes to more serious subluxation and ultimately dislocation of the toes at the MPJ with partial or complete disruption of supporting soft tissue structures.
Typically, there are varying injuries to the soft tissues including joint capsule, plantar plate and/or collateral ligaments, which can become attenuated or torn. Less common are injuries to the extensor and/or flexor tendons, which we commonly overlook. Due to joint instability, one can encounter chondral and osteochondral joint lesions as well. In any athlete who presents with ball of foot pain and/or digital deformity, always consider lesser MPJ instability. Without early recognition, progression of the deformity can occur, making treatment protocols more challenging with less predictable outcomes. This problem can be devastating to the athlete as morbidity can be significant, adversely affecting an athlete’s training and playing ability for an extended period of time.
Pearls On Confirming The Diagnosis
Before considering treatment options, one should efficiently establish a diagnosis and validate it with imaging studies if possible. It is important early on to acquire pertinent information from the clinical evaluation that will help to establish a rational treatment program. This information includes: the duration of injury, etiology, predisposing factors, pain level, functional activity level and the stage/severity of injury.
The duration of injury can be acute, subacute or chronic. For the sake of this discussion, I define acute as less than two weeks, subacute as two to six weeks and chronic as greater than six weeks. The clinician also needs to differentiate whether this is a new or recurrent injury (e.g., acute or chronic episode). The longer the duration of articular instability without treatment, the more potentially severe the toe deformity and the patient’s symptoms.
The etiology can be due to macrotrauma (sudden hyperextension injury due to fall), microtrauma (overuse), attrition (wear and tear) or iatrogenic (intra-articular acetate steroid injection).
Predisposing factors can include systemic and mechanical factors. Systemic factors would include generalized ligamentous laxity, rheumatic and neuromuscular diseases. Mechanical factors would include ankle equinus, hallux abducto valgus with bunion deformity, a hypermobile first ray, an excessively long metatarsal, metatarsal transverse plane malalignment with abnormal digital deviation angle and forefoot equinus (anterior cavus) deformity. I feel forefoot equinus is the most common and significant predisposing factor due to the effects of extensor substitution, which causes the single strongest deforming force on the lesser MPJs.
Pain level is based on the Visual Analogue Scale (VAS) of 0-10, which indicates severity of pain. This is an important outcome measure as the more severe the pain, the more aggressive the treatment.
The functional activity level typically parallels the pain level as the more pain the patient experiences, the more the patient’s activity level is compromised. Return to activity protocols can determine an athlete’s ability to return to specific activities.
Staging/severity of injury is based on clinical evaluation and diagnostic imaging (weightbearing X-rays, arthrograms, magnetic resonance imaging, ultrasound, etc.) to determine the degree of articular instability/injury and which soft tissue structures are involved.
Two important clinical tests to assess for sagittal plane instability are based on performance of the Lachman maneuver and toe purchase test. The Lachman maneuver is a sagittal plane stress maneuver in which one applies a dorsal vertical force to the proximal phalanx base and a plantar vertical force to the metatarsal neck/head. Staging is as follows and is based on the Bouché/Heit Classification.1
Stage 0. No instability is evident on exam but extensus of toe may be present.
Stage 1. The toe is subluxable on exam. Consider the toe as stage 1A if less than 50 percent subluxation is present and as stage 1B if there is more than 50 percent subluxation.
Stage 2. The toe is susceptible to dislocation.
Stage 3. The toe has fixed dislocation.
The toe purchase test evaluates both static position of toe at rest while standing and dynamically evaluates ability of toe to maintain ground contact when performing a pull-out maneuver with a piece of paper or tongue depressor.
What To Consider In Formulating A Treatment Plan
After carefully considering this information, then one can discuss and establish a treatment plan. Paramount to this discussion would be an appreciation of the athlete’s goals and expectations. Typically, these patients have high expectations and demands with aspirations of returning to full athletic activities in their respective sport without limitations. The physician and patient should agree to well understood and well established treatment plans prior to initiation. Discuss and clearly define anticipated outcomes for treatment rendered as this pathology will challenge the best of physicians.
Regardless of whether you decide upon a surgical or non-surgical approach, one can start with specific conservative care strategies and be successful (see “A List Of Conservative Treatment Strategies” at left). These non-surgical strategies can be the primary treatment or they can be a temporary stopgap intervention before surgery can occur. The purpose of this article is to share non-surgical treatment options I have found to be effective in treating symptoms of lesser MPJ instability. These treatments have proven to me to be very effective in treating pain and functional limitations, and mitigating the progression of deformity.
We must realize that despite clinical improvement, we are not correcting the soft tissue deficiency/toe pathology per se. The deformity still exists but the treatment is successfully accommodating it. This accommodation period can be short-lived or be successful over an extended period of time. Beyond this point, management will be based on pain and functional activity levels, which will dictate whether surgery would be indicated.
In reviewing the literature on the management of lesser MPJ instability, there are a few articles evaluating non-surgical care with published papers offering level IV and V evidence with small patient numbers and varied results.2-6 There is one level III evidence paper, a large prospective comparative case series, published in 2012, that underscores the importance and significance of non-surgical care versus surgical care for lesser MPJ instability.7 The study reviewed 75 patients treated non-surgically (with varied isolated and combined treatments rendered) with 52 percent of patients being either satisfied or very satisfied with their treatment. The authors were not able to show any difference between non-surgical and surgical intervention with regard to pain and function outcomes. They thought most patients could receive non-operative treatment.
Keys To Treating Acute/Subacute Lesser MPJ Instability
The following discussion is based on my personal experience with non-surgical management of lesser MPJ instability in athletes over a more than 30-year time period. The reader will find some recommendations and strategies to be familiar and some may be new and different. I have discovered many of these treatments serendipitously and as these treatment plans continue to evolve, high-level studies will be needed to validate their efficacy in the treatment of lesser MPJ instability.
Conservative treatments fall into two categories: acute/subacute and chronic. Most of what I see in my sports medicine practice is the chronic variety of instabilities.
For the acute/subacute category, initially, the patient will typically need a period of acute phase treatment to decrease inflammation from the initial insult and stabilize the injured MPJ. Strategies would include “PRICE” — Protection, Rest, Ice, Compression and Elevation.
Protection can occur through a removable short leg walking boot with a flat footbed. Flat footbeds allow patients to position the toes neutral in the sagittal plane. Commonly used concave footbeds put the toes in an extended position (increased toe spring), which is not desirable as the treatment goal is to take tension off affected plantar soft tissue structures. An over-the-counter or custom orthosis within the boot can accommodate painful areas. The use of toe taping with ½-inch paper tape or commercial splints can plantarflex affected toes, which takes tension off painful plantar soft tissues and limits toe extension. One can treat transverse plane deformities with toe spacers to realign the digit into a neutral position.
Rest is typically relative with the athlete participating in daily activities as tolerated. While the patient uses a short leg walking boot, he or she will not be able to participate in weightbearing sport activities but may be able to participate in select non-weightbearing activities. Full non-weightbearing immobilization is rarely needed.
Patients should use ice when swelling is significant.
Compression of the forefoot with a small 2-inch Ace wrap or compression stocking works well. Coban elastic compression wrap application can mitigate swelling of the toes.
Elevation above heart level when recumbent can also be beneficial when athletes perform it on a regular basis. Medications to address inflammation (nonsteroidal anti-inflammatory drugs and oral steroids) and pain (analgesics) can be beneficial, and patients can use topical or oral medications. I do not recommend steroid injections in the acute/sub-acute phases due to their potential deleterious effects on collagen healing.8 Researchers have previously documented joint dislocation secondary to intraarticular joint injection.9 Acute phase treatment can continue for one to four weeks depending on the nature and severity of the injury.
A Guide To Treating Chronic Lesser MPJ Instability
Beyond the acute phase treatment, clinicians can initiate treatment for longer-term chronic injuries. These treatments are based on the specific diagnosis and predisposing factors.
In regard to shoewear, an external forefoot rocker will help unload the ball of the foot. One can add an external forefoot rocker to an existing shoe or purchase a rigid forefoot rocker sole shoe. Clinicians can convert shoes that are flexible at toe break and add an adequate intrinsic rocker to a rigid rocker by placing a pre-cut Carboplast plate (AliMed) (my preferred material versus graphite, which I feel is too rigid) in the shoe. This will render the shoe more rigid by minimizing toe break flexibility. I recommend a positive drop-sole (higher in heel than forefoot) design or the use of heel lifts in neutral drop shoes for the forefoot equinus foot type. For patients with bunion/bunionette deformity, split last shoes (wide forefoot, narrow heel) can be accommodative. An adequate toe box width and depth can also help in accommodating digital deformities. Full-grain leather shoes can also stretch to accommodate these deformities.
Foot orthoses, either OTC or custom, can also aid in unloading painful MPJs and addressing predisposing biomechanical aberrations. Forefoot accommodations on the orthoses can include cushioned extensions, metatarsal head “cutouts” with soft backfill, metatarsal pads or “cookies,” etc. Full-contact (with minimal arch fill) semi-rigid polypropylene custom orthoses with a deep heel cup are preferred. Scan or cast feet in a neutral position with the first ray plantarflexed. Orthoses should be low profile to allow use in all shoe types including athletic, casual and dress shoes.
Calf stretching and the use of night splints can be beneficial for patients with ankle equinus. Aggressive sustained stretching of the extensor tendons, especially the extensor digitorum longus tendon, can be extremely beneficial, especially in patients with forefoot equinus deformity. The patient assuming a sitting position (butt on feet with knees flexed) provides an effective and aggressive strategy in this regard.
Oral and topical medications to address inflammation (NSAIDs and steroids) and pain (analgesics), especially acute-on–chronic episodes, can be beneficial. When it comes to intraarticular or periarticular injections of the lesser MPJs, I recommend a phosphate steroid. Avoid acetate steroids (especially triamcinolone acetonide in my opinion) as spontaneous joint subluxation and dislocation are not uncommon. Various authors have reported this concern in the literature although articles relating to this are scarce.1,10,11
Depending on the severity of symptoms and deformity, consider temperance of activities. Patients should limit weightbearing activities that are continually painful or eliminate them for a period of time and consider non-weightbearing activities (i.e., swimming, cycling, rowing, etc.). Consider return to activity evaluation protocols as these protocols provide objective criteria for return to activities.
Concerning toe splints, various toe splinting techniques are available. Repositioning lesser toes from an extended to a neutral or plantarflexed position can be invaluable, especially for flexible sagittal plane deformities and instability of toes. Taping toes with ½-inch hypoallergenic paper tape provides a fast and easy method to mitigate sagittal plane deforming forces. Patients should apply taping to each individual affected toe separately. Taping can be effective for transverse plane deformities as well but I prefer toe spacers for transverse plane deformities. When taping is contraindicated or not tolerated, the use of various commercial splints can be beneficial. The Budin-type toe splints can be helpful, especially if the toe deformity is flexible and reducible. Bunion splints can also be helpful for addressing lateral drifting or abductus of the hallux by stretching laterally contracted soft tissues. I typically recommend them for nighttime use while sleeping.
Toe spacers provide an excellent way to reposition the toe in a neutral transverse plane position. They generally come in small, medium and large, and are made of foam, rubber or silicone of various shapes. Some even have an attached elastic toe sleeve to prevent displacement during activities.
Metatarsal binders or corsets are soft elastic sleeves either of a fixed “pull-on” variety or an adjustable Velcro closure type that fit snugly around the “waist” of the foot (between the instep and ball). Use this strategy for patients with a wide, flexible forefoot and first ray hypermobility or instability. The sleeve imparts a compression or squeezing effect on the metatarsals in the transverse plane, essentially decreasing forefoot splaying and stabilizing the first metatarsal.
In most cases, clinicians will begin multiple treatment strategies based on the specific diagnosis and the presence of predisposing factors. If a patient decides to live with the problem, these strategies continue indefinitely to mitigate symptoms in a symptomatic patient and prevent symptoms in an asymptomatic patient. These patients, due to altered function with gait compensation and guarding, commonly suffer from generalized lower extremity soreness and fatigue despite the use of the aforementioned treatments. A variety of soft tissue mobilization techniques can be beneficial in these cases to complement the treatments I have discussed. These include deep massage, augmented massage, muscle activation, active release and myofascial release to name a few. Working in concert with a manual physical therapist and/or massage therapist can result in a winning situation for all involved.
Though there is only one level III study to validate the efficacy of non-surgical strategies in addressing lesser MPJ instability, I recommend that readers consider the treatment strategies discussed in this article as an initial step in dealing with the various clinical presentations of lesser MPJ instability. Results of these treatments have been better than expected when using pain and function as outcome measures. These conservative care measures address pain and function issues while not directly addressing the actual soft tissue deficiencies and osseous deformities. Long-term follow-up will determine if this initial success with conservative care can withstand the effects of time.
Dr. Bouché is a Fellow and Past President of the American Academy of Podiatric Sports Medicine. He is a Fellow of the American College of Foot and Ankle Surgeons, and is in private practice in Seattle.
- Bouché RT, Heit EJ. Combined plantar plate & hammertoe repair with flexor digitorum longus tendon transfer for chronic, severe, sagittal plane instability of the lesser metatarso--phalangeal joints: preliminary observations. J Foot Ankle Surg. 2008; 47(2):125-137.
- Mann RA, Mizel MS. Monoarticular nontraumatic synovitis of the metatarophalangeal joint: a new diagnosis? Foot Ankle. 1985; 6(1):18-21.
- Coughlin MJ. Crossover second toe deformity. Foot Ankle. 1987; 8(1):29-39.
- Coughlin MJ. Second metatarsophalangeal joint instability in the athlete. Foot Ankle. 1993; 14(6):309-319.
- Trepman E, Yeo S. Non-operative treatment for metatarsophalangeal joint synovitis. Foot Ankle. 1995; 16:771-777.
- Mizel MS, Michelson JD. Nonsurgical treatment of monoarticular nontraumatic synovitis of the second metatarophalangeal joint. Foot Ankle Int. 1997; 18(7):424-426.
- Peck CN, Macleod A, Barrie J. Lesser metatarsophalangeal instability: management and outcomes. Foot Ankle Int. 2012; 33(7):565-570.
- Dean BJ, Lostis E, Rombach I, et al. The risks and benefits of glucocorticoid treatment for tendinopathy: a systematic review of the effects of local glucocorticoid on tendon. Semin Arthritis Rheum. 2014; 43(4):570-576.
- Reis ND, Karkabi S, Zinman C. Metatarsophalangeal joint dislocation after local steroid injection. J Bone Joint Surg Br. 1989; 71(5):864.
- Yu VY, Judge MS, Hudson JR, et al. Predislocation syndrome- progressive subluxation/dislocation of the lesser metatarsophalangeal joint. J Am Podiatr Med Assoc. 2002; 92(4):182-199.
- Templar H, Gehwolf R, Lehner C, et al. Effects of crystalline glucocorticoid triamcinolone acetonide on cultured human supraspinatus tendon cells. Acta Orthop. 2009; 80(3):357-362.